1. Field of the Invention
The present invention generally relates to medical devices and methods, and more particularly relates to illuminated surgical instruments such as illuminated surgical retractors and handheld instruments such as illuminated suction devices. One of skill in the art will appreciate that these examples are not intended to be limiting and that other illuminated instruments or tools are also contemplated.
There are various surgical devices in the market that provide illumination to a surgical field. A number of these devices are either manufactured from a bundle of fibers or a single fiber. In the operating room, modern light sources are used to produce a tremendous amount of illumination intensity. This energy is coupled into these illumination products, which transmit the light over a distance and then the energy is output onto the surgical surface.
In certain circumstances, these devices can create a thermal danger to the patient, the user, or the equipment being used. When all the optical energy from a fiber bundle is focused on a patient, tissue can dry out, and the heat generated can also result in burns. Surgical drapes have been reported to melt and catch on fire in the operating room. During surgical procedures, blood, other debris, or surgical drapes may obstruct the device and block light output. Obstructing light creates several issues. The first is reduction of illumination on the field, thus minimizing the visual acuity of the task. This obviously can affect the efficiency of the procedure. A more critical issue however is thermal buildup on the section of the illumination device which is obstructed. Since the light cannot exit, it converts to heat as it is blocked. Blood, for example, coagulates at an average temperature of 40° C., so as it coagulates on the surface of the illumination device it will block light output minimizing the amount of light exiting the device. The increased energy density will also further heat up the device. Fiber bundles are often fabricated from glass which may not be affected by this, but adhesives used in the fiber bundle assembly may be damaged from the heat, and when the fiber bundles are fabricated from polymers, the fibers may heat up and melt or exceed the glass transition temperature and deform. Therefore it would be desirable to provide illuminated surgical instruments that are able to control heat generated so as to avoid damaging the illuminated surgical instrument, as well as avoiding harming the patient or operator. In the example of the surgical drape, if the drape is obstructing the illumination element, the energy density on the drape is much higher for several reasons. As mentioned earlier the illumination element heats up if the drape is actually touching the illumination element. The other reason is that if the drape is very close to the illumination element and there is air space, the energy density of light being absorbed by the drape is so high that it will melt the drape when compared to a drape that is disposed further away from the illumination element and the light is dispersed over a larger area on the drape.
Therefore, it would be desirable to provide a device that has a low energy density output. Energy density may be controlled by increasing the surface area from which the light is delivered, thereby reducing the heat generated. However, an increase in surface area may increase the overall profile of the surgical device. This may be undesirable because a larger surgical device may occupy too much space in the surgical field, thereby requiring a larger incision which is undesirable. Thus, with ever decreasing surgical incision sizes, it would also be advantageous to provide an illuminated surgical instrument with a low profile so as to avoid obstructing the surgical field.
At least some of these objectives will be satisfied by the devices and methods disclosed below.
2. Description of the Background Art
Illuminated surgical instruments may include illumination elements such as fiber optics, optical waveguides, or other means for providing the light. Optical waveguides and fiber optics are well known in the art.